The Halloween pumpkin must be one that hasn’t been cut into because bacteria can start to grow. I roasted the pumpkin halves in the oven for a couple of hours at 350. I scooped out the pulp and used my blender to puree it after it cooled in batches. I figured that 3 cups of pulp equals a can and made 2 pies today, they turned out fine. A little different texture but still tasty.
(I let my pumpkin purée sit in the fridge over night and spooned off some of the moisture that seeped out before using.)
The only problem I can see is the amount of purée a basketball pumpkin gave me. I have about 6 cups left to use in maybe pumpkin loaves or muffins.